Analysis of the effect of tubing material and external insulation to wax deposition formation in vertical waxy oil well

Abstract

Flow Assurance is a nomenclature in the oil and gas industry which can be interpreted as guaranteeing the success of hydrocarbons (oil and gas) flowing from the reservoir to the point of sale and avoiding flow assurance issues, one of them is due to wax deposition [1]. Waxy oil, also known as HPPO (High Pour Point Oil) is an incompressible type of oil, with high saturate, aromatic, and paraffin content [2]. In principle, waxy oil will form a wax deposit, either in the pipe or tubing if the temperature of the flowing fluid has touched the Wax Appearance Temperature (WAT), or the highest temperature at which the wax particles begin to precipitate [1]. This research was conducted using synthetic databases collected from several published journals with the aim of modelling the flow of waxy oil in vertical onshore production wells, identifying problems that may occur during the oil production, simulating the starting point of wax deposition, and comparing several scenarios regarding the factors that affect deposits. The results of this study indicate that one of the most influential parameters in the process of forming wax deposits is when the fluid temperature is below the Wax Appearance Temperature (WAT). The simulation results from the scenarios, it is found that the higher the thermal conductivity of a tubing material, the faster the wax deposition occurs, and produces the highest thickness of wax deposits. Other research results obtained are, with simulations using insulation, show that tubing with an insulating material Fiberglass with a high insulation thickness is proven to be the most effective in preventing the wax deposition process. The presence of wax deposits in the tubing has a negative impact, one of which is a reduction in the inner diameter of the tubing, so that it will reduce the flow rate, and which in the end the wax will create a plug which makes the crude oil unable to be produced again. The results obtained from this study are differences in tubing material and the use of insulators will affect the deposition of wax that occurs.